With the development of the Internet of Things, the number of machine-to-machine (M2M) devices increases as well. The standardization organization 3rd Generation Partnership Project (3GPP) specially establishes a project team “Provision of low-cost MTC UEs based on LTE”, which studies low-cost machine type communication (MTC) terminals based on Long Term Evolution (LTE). The research on low-cost MTC terminals based on LTE mainly considers enhancement or optimization of an LTE network and an air interface with respect to the introduction of MTC devices, where a coverage issue is one of key concerns of operators. In view of cost and frequency spectrum factors, operators put forward new demands: in comparison with a current LTE system, coverage of the LTE system needs to be enhanced by 20 dB when the LTE system provides services to an MTC terminal.
Aiming at the demand of operators for a 20 dB coverage enhancement of the LTE system, a repetition manner is adopted in the prior art to enhance an LTE physical channel. Taking a physical downlink control channel (PDCCH) with coverage enhancement or an enhanced physical downlink control channel (ePDCCH) with coverage enhancement as an example, a coverage enhancing method is: a base station repeatedly sends downlink control information (DCI) carried on a PDCCH or an ePDCCH in control channel elements (CCE) or enhanced control channel elements (eCCE) in N (N is a positive integer) consecutive subframes, and an MTC UE combine information content of the CCEs or eCCEs received in the N subframes, and performs detection, thereby improving detection performance. Such detection of a PDCCH or an ePDCCH with coverage enhancement requires that a UE firstly extract CCE or eCCE information, of the PDCCH or ePDCCH with coverage enhancement, mapped into the N subframes, then combine the CCE or eCCE information content in the N subframes, and finally perform decoding.
It can therefore be seen that, the UE may know whether its own DCI exists only after detecting the PDCCH or ePDCCH, that is, the UE may know whether a base station sends the DCI to the UE by detecting the PDCCH or ePDCCH in each subframe or detecting the PDCCH or ePDCCH with coverage enhancement in the subframe where the PDCCH or ePDCCH with the coverage enhancement is located. However, the base station may not send the DCI to all UEs; therefore, the DCI of the UE does not always exist in one subframe or in the subframe where the PDCCH or ePDCCH with coverage enhancement is located, but all UEs may need to detect the PDCCH or ePDCCH, which is undoubtedly a waste of the power of these UEs. Especially for the MTC UE, the PDCCH or ePDCCH with coverage enhancement requires extraction of a mass of information and complex blind detection; and if the MTE UE does not find its own DCI after detection and when N is very large, the waste of the power consumption of the MTC UE is serious, which is adverse for the MTC UE powered by a battery.